Simon Magus sought to buy divine power (Acts 8:18-24), but learned that the gifts of God cannot be purchased with money. The water of life may be taken freely by all who desire to do so (see Rev. 22:17). The disciples were not to make a profit from preaching the gospel, yet at the same time they were to remember that “the workman is worthy of his meat” (see on Matt. 10:10).
Heal the sick.
Christ enumerates the various types of miracles the disciples had so often seen Him perform. All that He had done, they were to do. Demons and even death itself were to be subject to them.